Convert aos over to flatbuffers

Everything builds, and all the tests pass.  I suspect that some entries
are missing from the config files, but those will be found pretty
quickly on startup.

There is no logging or live introspection of queue messages.

Change-Id: I496ee01ed68f202c7851bed7e8786cee30df29f5
diff --git a/aos/vision/image/image_dataset.cc b/aos/vision/image/image_dataset.cc
index d4dde95..33bf0e4 100644
--- a/aos/vision/image/image_dataset.cc
+++ b/aos/vision/image/image_dataset.cc
@@ -37,10 +37,10 @@
   res.reserve(pos.size() + 1);
   i = 0;
   for (auto p : pos) {
-    res.emplace_back(inp.substr(i, p - i).to_string());
+    res.emplace_back(std::string(inp.substr(i, p - i)));
     i = p + 1;
   }
-  res.emplace_back(inp.substr(i).to_string());
+  res.emplace_back(std::string(inp.substr(i)));
   return res;
 }
 }  // namespace